Distributed evenly around the whole surface of the retina.
Approximately 125 million rod cells in the eye.
Highly concentrated around the fovea.
Approximately 6 million cone cells in eye.
Structure
An elongated rod shaped cell.
An elongated cell with a conical ending.
Function
Very sensitive to light allowing for the absorption of light.
Suited for night vision when not much light present to provide black and white images to the brain.
Distinguish between colors.
Not very sensitive to light.
Not effective when minimal light is present.
Figure 10.1 representing rod cells, in blue, and cone cells, in green. The rod cell is a long rod shaped cell while the cone cell is a long cell with a conical ending.
Aubusson, Eileen Kennedy Peter. Biology in Context: the Spectrum of Life. Victoria : Oxford Uni. Press., 2001. Print.
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